Composite strength-accelerating material.



EDWARD L. ooNwELL, or UPLAITD, PENNSYLVANIA, ASSIGNOR T0 ALUMINATE rarmrrs COMPANY, or PHILADELPHIA, PENNSYLVANIA, A conronarron or nnw JERSEY.

COMPOSITE STRENGTH-ACCELERATING -MATERIAL 1,185,775. No Drawing.

To all whom it may concern Be'it known that I, EDWARD LJCONWELL, a citizen of the United Statesand resident of Upland Chester, Delaware county, Pennsylvania, have made a certain new and useful Invention relating to Composite terial such as alkali metal disulfates and also relates to the manufacture thereof as by grinding together or otherwise intimately incorporating the components. vSuch combined strength accelerating material is desirable for use when mixed or incorporated with cementitious materials, such as plasters comprising hydrated or otherwise available lime, the strength accelerating material effecting improvement in working properties such as the plasticity, reliability, cementitious properties. and early strengths of the material so as to be especially desirable in plaster compositions for wall plastering and so forth. Suitable energizing materials of this class, that is,. compounds apparently having loosely combined or otherwise available sulfuric acid or sulfuric 'anhydrid and which are herein referred to as supersulfates, such for example, as potassium disulfate (K S O.,) ,or its more hydrous vari-'* ant potassium bisulfate (KHSOQ), sodium disulfate (Na S O,),the related sodium bi-' sulfate (NaHSOQ, ammonium bisulfate f nmnson; ferric sulfate A 008),

and acid calcium sulfate, preferably in their commercial or crude forms, such as n'iter cake, acid calcium sulfate sludge, and so "forth, seem to have desirable energizing action on fused slow setting calciumaluminate and other alummous and s1l1c1ous strength accelerating material when incor-' porated therewith, so as to increase and hasten the strength accelerating and cementitious action of such material on cooperating cemen'titious material comprising hydrated or otherwise available lime. This seems .to be due .to the supersulfate ener gizing material action upon and disintegrating or opening up the strength accelerating I Specification of Letters Patent.

Patented; June 6, 1916.

Application filed November 7, 1912'. Serial No. 729,981.

material, possibly because of its availableloosely combined sulfuric anhydrid, either with or without water unitedtherewith, thus apparently promoting the activity of certain hydraulic elements and their solubility in alkaline solutions of the material present, or rendering them more active in connection wlth the lime component of the cooperating cementitious material. Such supersulfate energizing material heir incorporated to the extent of a few per cc: ,t. more or less, for

example, with Wall. plaster compositions comprising about 85 parts of hydrated lime and '15 parts or'so of fused slow setting calclu'm alumlnate material containing con.-

*side rable silica which is preferably water granulated or quickly cooled, materially promotes the cementitious' properties and hydraullc set thereof and makes the compositiolis more desirable for use, especially under extreme service, where for example conditions tend to promote excessive drying out. Many such cooperating energizing materials conta ning simllarly available loosely combined sulfuric anhydrid or sulfuric acid not only increase the cementitions properties and early strengths of the lime and aluminate or other calcareous mixtures, but also promote. their plasticity, reliability and spreading properties and their hardening and substantially uniform,: homogeneous setting. It is desirable that the fused calcium aluminate or other strength acceleratother energizing material containing avail- 7 ing material and the sodium disulfate or W able acid should be ground together orother- 9 wise thoroughly incorporated, which seems to promote the initiation of chemical action to the extent permitted by the presence of the usual small proportion of water therein, and the opening up or disintegration of the strength accelerating material. The, strength accelerating action occurring when the plastor compositions or other calcareous cementitious materials in which such prepared materials are incor orated, are gaged and tempered, is possibly increased because of the further chemical interaction of the acid andf'other components and the decomposition or liberation of the aluminous, silicious or other hydraulic components in such form a as to more readily exert cementitious or hydraulic action in connection with the lime and so forth. Besides securing an extremely intimate and desirable incorporation of the calcium aluminate or the like'and any suit able cooperating energizing material containing loosely combined or available sulsuitable for mixture in desired proportions with hydrated lime or other cooperating calcareous cementitious material. Hydrated lime plaster compositions prepared in this way by the incorporation of ten to twenty per cent. or so of fused slow setting calcium aluminate strength accelerating material and about one-thirtieth to one-sixth as much cooperating sodium disulfate energized material, are extremely satisfactory from the practical working standpoint, and possess many of the desirable features of ordinary lump lime putty plasters including plasticity, ease of working andlarge sand carryingproperties, besides being much more convenient to prepare for use, quicker hardening and having greater early strengths and cementitious or'hydraulic properties and being more durable and reslstant to freezing and other weather conditions.

' sulfate energizing material may be advantageously mixed or incorporated in any desired way, preferablyby grinding or oth erwise intimately mixing, with various cementitious materials comprising free Or available lime, such for example, as with so forth, or with pozzuolanic or other cements in connection'with any calcium aluminate'or earthy alkali strength accelerating compounds of alumina and iron or other alumina-like material, such as are referred to in the Spackman-Lazell Patents 903,017, 903,018, 903,019 and 903,020, of November 3, 1908 and 1,029,953 and 1,029,954 of June 18,

1912, on which this invention is based;'and\ in which it is indicated that iron or similar material may be used in some cases to re place to some extent at least-the alumina in such strength accelerating material, and that other'earthy alkali material, such as magnesia and so forth, may be submitted for part at least oftho lime combined therewith, such calcium aluminates and equivalent or substitute accelerating material being designated hydraulic earthy alkali accelerating compounds of alumina-like material, In the case of hydrated lime plaster compositions the lime and strength accelerating and energizing materials may with advantage be crushed together or intimately incorporated Such super I and the compositions simultaneously densified as described at length and claimed in the application of Spackman and Lazell,

Serial No. 698,906, filed May 22, 1912.

Various supersulfate energizing materials may also be used with relatively large proportions of fused or other calcium aluminate material or the like, incorporated with relatively small proportions of lime and also early strengths and improve the plasticity,

reliability and other properties of calcium aluminate hydrated limeplaster compositions, for example, and for this purpose the energizing material may be incorporated in varying proportions from a small fraction of a per cent. of sodium disulfate, for 'instance, which produces material energizing action, to several percent. or more. For general purposes good results are secured when s'uflicent sodium disulfate is incorporated with fused low lime calcium aluminate material containing considerable silica so that free or available sulfuric acid is thus provided to the extent of 3% to 5% or so of the total hydrated lime plaster composition containing 12% to 20% more or less of the calcium aluminate material.

An illustrative plastic composition may comprise 85'parts of hydrated .dolomitic lime and 15 parts of composite strength accelerat- 'ing material formed by grinding together pounds; at 7 days 90 pounds; at 28 days 90 pounds and at 3 months 105 pounds.

Magnesia (MgO)...... Calcium carbonate (0 O Calcium hydrate Ca OH)2) Sodium sulfate a1 0 Sulfuric anhydrid (S0 Mechanically contained water Water (H 0) Loss on ignition Another plaster composition containing a larger proportion of similar composite accelerating material was prepared by intimately incor orating parts of similar dolomitic hy rated lime with 25 parts of the supersulfate calcium aluminate strength accelerating material and when similarly terial and one part of acid calcium sulfate sludge, this material when similarly tested giving the following tensile strengths: at 24 hours pounds; at 2 days 53 pounds; at 7 days 62 pounds; at 28 days 66 pounds; at 3 months 68 pounds. a

Another illustratlve composition suitable for plastering purposes was forme d by intimately incorporating 85 parts of similar hydrated dolomitic lime with 15 parts of combined accelerating material formed by grinding together 1 part of sodium disulfate with 8 parts of fused calcium aluminate strength accelerating material having approximately the composition shown in the following analysis. This plaster material when similarly tested gave the following tensile strengths per square inch: at 24' hours 11 pounds; at 2 days 25 pounds; at 7 days 41 pounds; at 28 days pounds; at 3 -months.56 pounds. I

Silica (SiO 27.96

, Ferric oxid and alumina (R 0 20.60 Lime (CaO) 37.47 Magnesia (MgO) 11.66 Loss on ignition 1.08

Another illustrative. plaster composition was formed by thoroughly incorporating 85 parts of hydrated high calcium limewith combined strength accelerating material formed by grinding together 8 parts of fused low lime calcium aluminate with 1 part of sodium .disulfate. This material when tested under cement conditions with 4 parts of standard Ottawa sand gave the fol' lowing tensile strengths per square inch: at 24 hours 30 pounds; at 2 'days 52 pounds; at 7 days 68pounds; at 28 days 72 pounds; at 3 months 74 pounds.

Another illustrative plaster composition was formed by thoroughly incorporating 85 parts'of hydrated high calcium lime having; 7 about the composition shown in the follow-* ing table, with 15 parts of combined accel erating .material'form'ed by grinding'together 1 part of sodium disulfate" with 8 parts of calcium aluminate made by calcining together bauxite and limestone so that this calcium aluminate had substantially the composition shown in the following analysis. This composition when similarlytested v ter.

gave the following tensilestrengths: at 24 hours 32 pounds; at 2 days 53 pounds; at 7 days'7 7 pounds; and at 28 days 80 pounds.

High Calcium calcium aluminate. hydrated lime Silica (SiOz) 7. 64 1. 96 Ferric oxid and alumina (R 0 48. 52 v 96 Lime (CaO) 33. 36 71. 38 Magnesia (MgO) 1.24 1. 44 Sulfuric anhydrid (S0 .97 Loss on ignition 8. 04 24:36

rately: ground before being mixed or mechanically incorporated, and the composition when tested after being mixed with four parts by weight of Philadelphia bar sand gave the following tensile strengths:

at 24 hours 40 pounds; at 2 days 59 pounds;

at 7 days 100 pounds; and at 28 days 105 pounds. l I

The following results were secured by the use of such supersulfate energizing material with an illustrative high strength calcium aluminate cement containing small proportions of hydrated lime soasto make a strong cement suitable for various purposes. This cementitious composition combining 83 parts of such fused calcium aluminate material, 15 parts of hydrated lime and 2 parts of sodium disulfate gave when 1 part of the cement was tested in water with 3 parts of Ottawa sand;

at 24hours 200 ounds, at 3 days 327 pounds, at 7 days 260 pounds'and at 28 days 370 pounds tensile strength per square inch.

Such energizing materials as supersulfate or other material comprising free or available acid may be used in this way, not only with calcium aluminate accelerating material, but alsowithmany other strength accelerating or hardening materials containing alumina- T and silica, such, for instance, as trass, tufa,

raw or calcined clay-shale, or other natural, prepared or artificial pozzuolanic material,

and with natural or Portland cements,

bauxites, kaolins or other high aluminous material on which they seem to exert an energiz'ing action of possibly difierent characally nearly as good as the calcium alumi- While'such compositions are not 'u'sunat'e compositions,'-yet in many pages espe; ciall'y- 1f larger proportions of thecombined strength accelerating-materials are used'ithey can be practically employed for plastering purposes and have much greate'r'plasticity,

workability and ultimate strength than ordinary hydrated lime plasters.

A'plaster composition was made by incorporating with dolomitic hydrated lime 15% of the composite strength accelerating material comprising natural cement ground together with one-eighth as much sodium disulfate which produces a composition having good workability and spreading propgrinding together .1 part of sodium bisul erties and desirable hardening and early strengths so as to be much superior to a corresponding mixture of the natural cement and lime without the incorporation of the supersulfate energizing material. This composition when one part was tested with four parts of Ottawa sand gave the following tensile strengths per square inch: at 24 hours 7 pounds; at 2 days 22 pounds; at 7 days 27 pounds; at'28 days 32 pounds; at 3 months 62 pounds; the magnesian hydrated lime, the combined strength accelerating material comprising natural cement and sodium dis'ulfate, and the sodium disulfate energizing material used in the foregoing composition having about the following analyses:

. Natural cement: C o m b i n i n g Magnestrength acceler- S d! ating material 0 afi gg comprising eight g lime parts natural fate cement and one part sodium disulfate.

Silica (S10 2. 04% 26. 92% 1.5% Ferric oxid and alumina (R 0 0. 64% 10. 84% 0.2% 1Ifiime (C a(()]gi...) 4;. agnesia g 0 0 Calcium carbonate (CaC0 Calciumihydrate Ca(OI-I),) Sodium sulfate 212804) Sulfuric anhydrid (S0 Mechanically c o n t a i n e (1 water Water (H1O) Loss on ignition the following table. Another suitable plaster composition which had somewhat less satisfactory hardening properties when used as a wall plaster was made bysimilarly 1ncorpora ting with the 'same highcalcium hy-' drated lime 15% of. similar" composite strength accelerating material formed by fate with 8 vparts .of another natural ce- Loss on ignition ment designated No. 2 in the following table. This plaster composition when similarly tested gave the following tensile strengths: .at 24 hours 10 pounds; at 2 days 35 pounds; at 7 days 43 pounds and at 28 days 58 pounds.

Silica (SiO Ferric oxid and alumina (R20 Lime (CaO) Magnesia (MgO) Sulfuric anhydrid (S0 Loss on ignition An illustrative plaster composition formed by intimately incorporating parts of hy drated high calcium lime and 15 parts of strength accelerating material containing 1 part sodium disulfate and 8 parts of fused strength accelerating material containing alumina and silica and having approximately the composition shown by the following analysis gave when similarly tested the following tensile strengths; at 24 hours 12 pounds, at 2 days 37 pounds, at 7 days 55 pounds; at 28 days 57 pounds; and at 3 months 68 pounds.

Silica (SiO 31.80 Ferric oXid andaluinina (R O 15.68 Lime (CaO) 4 47.13 Magnesia (MgO) 2.22 Loss on ignition .84

.Another illustrative plaster composition of somewhat less strength was made by incorporating with hydrated dolomitic lime 15 per cent. of combined strength, accelerating material having substantially the composition shown in the following analysis and formed by grinding together one part of sodium bisulfate with 8 parts of roasted clay. This plastic material when tested in the usual wvay showed 28. pounds tensile strength per square inch at-7 days and 41 110 pounds at 28 day's.

Silica SiO 66.92 Ferric oxid and alumina (R O 17.26 Lime .(CaO) .79 Magnesia (MgO).- Trace Sulfuric anhydrid (80 6.82

7.28 It is of course understood that the strength tests given in connection with the-foregoing 12a examples must be'cjonsidered in connection with the extreme diflicultyof securing ,reliable'strength tests with lime plaster compositions. These tensile tests were made on briquets formed in the regular way for cement testing, the briquets being kept in air,

I but-in spite of. all possible precautlons considerablewariations arevlikely to'be'found insuch results and it is well understood that ;much more reliance must be placed on the practical Working results of such plaster compositions in which way their plasticity, sand carrying qualities, workability and hardening, setting, strength and reliability can'be determined in a more satis actory way, especially since high tensile strengths are not offirst importance in'ordinary plastering compositions provided the material develops at a relatively early period sulficient strength to certainly remain in position on the wall in spite of such disturbance or vibration as may be occasioned by setting the adj acentdoor frames or trim.

The invention has been described in this 1. The substantially dry finely divided composite strength accelerating material capable' when incorporatedtherewith of 1ncreasing the plasticity and cementitious properties and early strength of hydrated lime plaster compositions and COIIIPIlSlIlg' fused calcium aluminate strength accelerating material including silica which has been ground together with about one-eighth as much sodium disulfate'energizing material.

. 2. The substantially dry composite strength accelerating material capable when incorporated therewith of increasing the.

plasticity and cementitious properties and early strength of hydrated lime plaster compositions and comprising fused slow setting calcium aluminate strength accelerating-material and supersulfate energizing material..

3. The substantially I dry composite strength accelerating material capable when incorporated therewith of improving the plasticity and cementitious properties of hydrated lime plaster'compositions and comprising calcium aluminate strength. acceleratingmaterial" and alkali metal supersulfate energizing material.

4. The substantially dry composite strength accelerating material capable when incorporated therewith of improving working properties of hydrated lime plaster compositions and comprisingv calcium aluminate strength accelerating'material and supersulfate energizing material.

5. The composite strength accelerating material capable when incorporated therewith of improving working properties of -material capable when incorporated there-- with of improving working properties ofhydrated lime plaster compositions and comprising calcium aluminate strength accelerating material and about 5 to 15 per cent. as much supersulfate energizing material.

6. The composite strength accelerating material capable when incorporated therewith' of improving working properties of hydrated lime plaster compositions and comprising calcium aluminate strength. accelerating-material and about 5 to 15 per cent. as

much 'sodum disulfate energizing material;

1 7,. The composite strength accelerating material capable when incorporatedv therewith of improving working properties of hydrated lime plaster compositions and comprising strength accelerating compounds rich in alumina like material and cooperating supersulfate energizing material.

8. The composite strength acceleratingmaterial capable when incorporated therewith of improving working properties of hydrated lime plaster compositions and comprising strength accelerating compounds rich in alumina like material ground together with about 5 t o 15 per cent. as much alkali metal supersulfate energizing material.

9. The composite strength accelerating material capable when incorporated there withof improving working properties of hydrated lime'plaster compositionsand comprising strength accelerating compounds rich in alumina like material and cooperating e'nergizingmaterial comprising available sulfuric anhydrid loosely held in combination.

10. The composite strength accelerating material capable when incorporated therewith of improving the plasticity and cementitious properties of hydrated lime plaster compositionsand comprising strength accelerating material including alumina and silica which has been ground together with cooperating supersul'fate energizing material comprising available sulfuric anhydrid loosely held in combination.

11. The composite strength accelerating material capable when incorporated there with of improv ng the-plasticity and cementitious properties of hydrated lime plaster compositions and comprising strength accelerating material including alumina andv silica and cooperating energizing material comprising available sulfuric loosely held in combination.

12. The composite strength accelerating material capable when incorporated therewith of improving the plasticity and cementitious properties of hydrated lime plaster compositions and comprising strength accelerating material including alumina and cooperating energizing material comprising available sulfuric anhydrid loosely held in combination.

13. The composite strength accelerating hydrated lime plaster compositions and comprising calciumaluminate strengthacceleratanhydrid ing material which has been ground together with about 5 to 175 per cent. of alkali metal supersulfate energizing material.

14. The composite strength accelerating material capable when incorporated therewith of improving Working properties of hydrated lime plaster compositions and comprising calcium aluminate strength accelerating material which 'has been ground together with cooperating supersulfate ener- 10 gizing material.

EDWARD L. OONWELL.

Witnesses:

BENJAMIN H. LUDLoW, WILLIAM H. CREAMER, Jr. 

